网络协议安全对于互联网信息安全至关重要。目前主流的网络协议漏洞挖掘技术在安全性能、数据完整性、协议解析和逆向漏洞挖掘等方面还存在缺陷。模糊测试因其自动化程度高且能直接获得漏洞概念验证(Proof of Concept,PoC)的特点,在协...网络协议安全对于互联网信息安全至关重要。目前主流的网络协议漏洞挖掘技术在安全性能、数据完整性、协议解析和逆向漏洞挖掘等方面还存在缺陷。模糊测试因其自动化程度高且能直接获得漏洞概念验证(Proof of Concept,PoC)的特点,在协议安全测试中被广泛使用。然而,针对闭源协议的模糊测试,目前还缺少成熟的解决方案。因此,提出了NASFuzz模糊测试框架,能够对闭源NAS协议(NFS、NAS Find协议)进行漏洞挖掘。首先对闭源协议通信字段进行逆向,形成语法语义合规的模板;其次基于该模板,针对性变异字段中的非保留字段进行变异,生成大量的测试字段对协议进行测试。实验显示,NASFuzz模糊测试框架相比黑盒模糊测试框架BooFuzz,其有效样例生成数量高出70%以上,代码覆盖率提升18%,证明NASFuzz对NAS协议的测试相比传统黑盒测试更充分。展开更多
Solid-state Na metal batteries(SSNBs),known for the low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interf...Solid-state Na metal batteries(SSNBs),known for the low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interfacial contact in solid-state electrolytes has hindered the commercialization of SSNBs.Driven by the concept of intimate electrode-electrolyte interface design,this study employs a combination of sodium-potassium(NaK)alloy and carbon nanotubes to prepare a semi-solid NaK(NKC)anode.Unlike traditional Na anodes,the paintable paste-like NKC anode exhibits superior adhesion and interface compatibility with both current collectors and gel electrolytes,significantly enhancing the physical contact of the electrode-electrolyte interface.Additionally,the filling of SiO_(2) nanoparticles improves the wettability of NaK alloy on gel polymer electrolytes,further achieving a conformal interface contact.Consequently,the overpotential of the NKC symmetric cell is markedly lower than that of the Na symmetric cell when subjected to a long cycle of 300 hrs.The full cell coupled with Na_(3)V_(2)(PO_(4))_(2) cathodes had an initial discharge capacity of 106.8 mAh·g^(-1) with a capacity retention of 89.61%after 300 cycles,and a high discharge capacity of 88.1 mAh·g^(-1) even at a high rate of 10 C.The outstanding electrochemical performance highlights the promising application potential of the NKC electrode.展开更多
Elemental doping is an effective strategy for tuning the band structure of graphite carbon nitride(CN)to enhance its photocatalytic performance.In this study,sodium(Na)and oxygen(O)co-doped carbon nitride(Na/O-CN_(x),...Elemental doping is an effective strategy for tuning the band structure of graphite carbon nitride(CN)to enhance its photocatalytic performance.In this study,sodium(Na)and oxygen(O)co-doped carbon nitride(Na/O-CN_(x),x=1.0,2.0,3.0,4.0)was synthesized via solid-phase reaction of sodium citrate(NaCA)and pure CN powder in the Teflon-sealed autoclave under air conditions at 180℃.Surface area of Na/O-CN_(3.0) is measured to be 18.8 m^(2)/g,increasing by 60.7%compared to that of pure CN(11.7 m^(2)/g).Bandgap energy of Na/O-CN_(3.0) is determined to be 2.68 eV,marginally lower than that of pure CN(2.70 eV),thereby enhancing its capacity for sunlight absorption.Meanwhile,the incorporation of Na and O atoms into Na/O-CN_(x) is found to effectively reduce recombination rates of photogenerated electron-hole pairs.As a result,Na/O-CN_(x) samples exhibit markedly enhanced photocatalytic hydrogen evolution activity under visible light irradiation.Notably,the optimal Na/O-CN_(3.0) sample achieves a photocatalytic hydrogen production rate of 103.2μmol·g^(–1)·h^(–1),which is 8.2 times greater than that of pure CN(11.2μmol·g^(–1)·h^(–1)).Furthermore,a series of Na/O-CN_(x)-yO_(2)(y=0,20%,40%,60%,80%,100%)samples were prepared by modulating the oxygen content within reaction atmosphere.The catalytic performance evaluations reveal that the incorporation of both Na and O atoms in Na/O-CN_(3.0) enhances photocatalytic activity.This study also introduces novel methodologies for synthesis of metal atom-doped CN materials at lower temperature,highlighting the synergistic effect of Na and O atoms in photocatalytic hydrogen production of Na/O-CN_(x) samples.展开更多
Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yard...Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yardlong bean-like Fe_(9)Ni_(9)S_(16)/FeS heterostructures with sulfur vacancies encapsulated in N-doped carbon nanotubes(3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs)are controllably synthesized through Fe/Ni-catalyzed pyrolysis of dicyandiamide followed by sulfidation strategies.1D nanotubes with robust outer walls and internal cavity structures shorten the diffusion paths of ions/electrons and buffer volume expansion and aggregation of active materials.The Fe_(9)Ni_(9)S_(16)/FeS heterostructure provides a powerful driving force for charge transfer by forming built-in electric fields,optimizing ion adsorption,while the Fe_(9)Ni_(9)S_(16)features a wider interlayer spacing that allows for frequent Na+/Li+insertion and extraction,thereby enhancing the reaction kinetics within the electrode.Driven by these synergistic factors,the 3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs demonstrates remarkable electrochemical performance,achieving a substantial reversible capacity of up to 682.1mA h g^(−1)for SIBs at 0.1 A g^(−1)and 782.7 mA h g^(−1)for LIBs at 0.5 A g−1,alongside exceptional cycling stability in SIBs,maintaining 78.7%of its capacity after 1500 cycles at 1 A g^(−1)coupling with the ether-based electrolyte.Employing various electrochemical analyses in conjunction with ex-situ characterization techniques and Density Functional Theory(DFT)calculations,the storage mechanisms and phase transition processes are investigated,elucidating the structure-composition-performance relationships.This work paves the way for a new strategy in designing advanced materials with engineered heterostructures and controllable defects for energy conversion and storage devices.展开更多
文摘网络协议安全对于互联网信息安全至关重要。目前主流的网络协议漏洞挖掘技术在安全性能、数据完整性、协议解析和逆向漏洞挖掘等方面还存在缺陷。模糊测试因其自动化程度高且能直接获得漏洞概念验证(Proof of Concept,PoC)的特点,在协议安全测试中被广泛使用。然而,针对闭源协议的模糊测试,目前还缺少成熟的解决方案。因此,提出了NASFuzz模糊测试框架,能够对闭源NAS协议(NFS、NAS Find协议)进行漏洞挖掘。首先对闭源协议通信字段进行逆向,形成语法语义合规的模板;其次基于该模板,针对性变异字段中的非保留字段进行变异,生成大量的测试字段对协议进行测试。实验显示,NASFuzz模糊测试框架相比黑盒模糊测试框架BooFuzz,其有效样例生成数量高出70%以上,代码覆盖率提升18%,证明NASFuzz对NAS协议的测试相比传统黑盒测试更充分。
基金National Natural Science Foundation of China (52073253)。
文摘Solid-state Na metal batteries(SSNBs),known for the low cost,high safety,and high energy density,hold a significant position in the next generation of rechargeable batteries.However,the urgent challenge of poor interfacial contact in solid-state electrolytes has hindered the commercialization of SSNBs.Driven by the concept of intimate electrode-electrolyte interface design,this study employs a combination of sodium-potassium(NaK)alloy and carbon nanotubes to prepare a semi-solid NaK(NKC)anode.Unlike traditional Na anodes,the paintable paste-like NKC anode exhibits superior adhesion and interface compatibility with both current collectors and gel electrolytes,significantly enhancing the physical contact of the electrode-electrolyte interface.Additionally,the filling of SiO_(2) nanoparticles improves the wettability of NaK alloy on gel polymer electrolytes,further achieving a conformal interface contact.Consequently,the overpotential of the NKC symmetric cell is markedly lower than that of the Na symmetric cell when subjected to a long cycle of 300 hrs.The full cell coupled with Na_(3)V_(2)(PO_(4))_(2) cathodes had an initial discharge capacity of 106.8 mAh·g^(-1) with a capacity retention of 89.61%after 300 cycles,and a high discharge capacity of 88.1 mAh·g^(-1) even at a high rate of 10 C.The outstanding electrochemical performance highlights the promising application potential of the NKC electrode.
基金National Natural Science Foundation of China(21806023)Natural Science Foundation of Hunan Province(2021JJ40199)+2 种基金Education Department Foundation of Hunan Province(20C0813)Hunan University of Science and Technology Fundamental Research FundsPostgraduate Scientific Research Innovation Project of Hunan Province(CX20240877)。
文摘Elemental doping is an effective strategy for tuning the band structure of graphite carbon nitride(CN)to enhance its photocatalytic performance.In this study,sodium(Na)and oxygen(O)co-doped carbon nitride(Na/O-CN_(x),x=1.0,2.0,3.0,4.0)was synthesized via solid-phase reaction of sodium citrate(NaCA)and pure CN powder in the Teflon-sealed autoclave under air conditions at 180℃.Surface area of Na/O-CN_(3.0) is measured to be 18.8 m^(2)/g,increasing by 60.7%compared to that of pure CN(11.7 m^(2)/g).Bandgap energy of Na/O-CN_(3.0) is determined to be 2.68 eV,marginally lower than that of pure CN(2.70 eV),thereby enhancing its capacity for sunlight absorption.Meanwhile,the incorporation of Na and O atoms into Na/O-CN_(x) is found to effectively reduce recombination rates of photogenerated electron-hole pairs.As a result,Na/O-CN_(x) samples exhibit markedly enhanced photocatalytic hydrogen evolution activity under visible light irradiation.Notably,the optimal Na/O-CN_(3.0) sample achieves a photocatalytic hydrogen production rate of 103.2μmol·g^(–1)·h^(–1),which is 8.2 times greater than that of pure CN(11.2μmol·g^(–1)·h^(–1)).Furthermore,a series of Na/O-CN_(x)-yO_(2)(y=0,20%,40%,60%,80%,100%)samples were prepared by modulating the oxygen content within reaction atmosphere.The catalytic performance evaluations reveal that the incorporation of both Na and O atoms in Na/O-CN_(3.0) enhances photocatalytic activity.This study also introduces novel methodologies for synthesis of metal atom-doped CN materials at lower temperature,highlighting the synergistic effect of Na and O atoms in photocatalytic hydrogen production of Na/O-CN_(x) samples.
基金supported by the program of National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and Future planning(grant number 2022R1A4A1034312,2023R1A2C1007413)by the Commercialization Promotion Agency for R&D Outcomes(COMPA)grant funded by the Korean Government(Ministery of Science and ICT)(RS-2023-00304764)。
文摘Tailoring 1D nanotubes with refined interfacial interactions and optimized adsorption sites presents a highly promising yet challenging strategy for advancing Na/Li-ion batteries(SIBs/LIBs).Herein,the intertwined yardlong bean-like Fe_(9)Ni_(9)S_(16)/FeS heterostructures with sulfur vacancies encapsulated in N-doped carbon nanotubes(3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs)are controllably synthesized through Fe/Ni-catalyzed pyrolysis of dicyandiamide followed by sulfidation strategies.1D nanotubes with robust outer walls and internal cavity structures shorten the diffusion paths of ions/electrons and buffer volume expansion and aggregation of active materials.The Fe_(9)Ni_(9)S_(16)/FeS heterostructure provides a powerful driving force for charge transfer by forming built-in electric fields,optimizing ion adsorption,while the Fe_(9)Ni_(9)S_(16)features a wider interlayer spacing that allows for frequent Na+/Li+insertion and extraction,thereby enhancing the reaction kinetics within the electrode.Driven by these synergistic factors,the 3 N-Fe_(9)Ni_(9)S_(16)/FeS-3@CNTs demonstrates remarkable electrochemical performance,achieving a substantial reversible capacity of up to 682.1mA h g^(−1)for SIBs at 0.1 A g^(−1)and 782.7 mA h g^(−1)for LIBs at 0.5 A g−1,alongside exceptional cycling stability in SIBs,maintaining 78.7%of its capacity after 1500 cycles at 1 A g^(−1)coupling with the ether-based electrolyte.Employing various electrochemical analyses in conjunction with ex-situ characterization techniques and Density Functional Theory(DFT)calculations,the storage mechanisms and phase transition processes are investigated,elucidating the structure-composition-performance relationships.This work paves the way for a new strategy in designing advanced materials with engineered heterostructures and controllable defects for energy conversion and storage devices.
